Syringe device with resistive ridges and methods of use

ABSTRACT

A syringe device incorporating ridges that cause resistive changes to the movement of the syringe gasket or plunger, thereby providing user feedback as to the position and speed of plunger movement. Such user feedback may be useful in stressful situations, under poor lighting conditions or in other unfavorable circumstances. Additionally, in certain embodiments these ridges may aid in accurate dispension or allow the syringe to derive additional functionality, such as performing as a vacuum source. Ridges can be protrusions such as tabs, bubbles or continuous rings for single or repeated use or these ridges may be formed as indentations. Ridges may be formed in patterns, in various sizes and shapes or these ridges may be mixed and matched as required or desired. Ridges may also be formed from a soluble material and the resistive change may itself provide indication that the material has been substantially dissolved and dispensed. In some embodiments these ridges are formed primarily within the barrel portion of the syringe. In other embodiments these ridges may be formed on the plunger stem of the syringe. Ridges may be constructed to provide one type of resistive change during the aspiration stroke and a different resistive change to motion in the opposite direction.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to a hypodermic syringeand more particularly to a syringe device having at least one ridgewithin the barrel portion of the syringe or along the plunger stem ofthe syringe device.

[0002] Syringe devices may be designed or intended for single orrepeated use and may be operated manually or all or a portion of theiroperation may be mechanized. In general, a syringe device is comprisedof three basic components: a barrel, which is typically cylindrical, aplunger, and a gasket which is affixed to the plunger so as to move inconjunction with the plunger. The gasket is typically designed tosubstantially seal within the barrel such that during operation theunits function as a displacement piston. As such, this pistonconfiguration provides for two directions of axial movement which maygenerally be termed an aspiration cycle and a dispensing cycle. Needles,filters, drive mechanism, locks, and protectors, as well as othercomponents, are often used to augment the basic syringe device.Commonly, the barrel portion is translucent to allow visualization ofthe contents such as medicinal fluids, body aspirates or glue.Accordingly, aspiration draws matter, such as fluids, into the syringe,or the negative pressure developed by the aspiration stroke may be usedfor other purposes, for example, to suction and hold parts beingmanipulated on an assembly line. Similarly, the opposite stroke providesan outward force that may be used, for example, to inject fluids, or toprovide a puff of air to blow dust off of optics. Combining pistonmovements with valves allows syringe devices to function in other ways,such as a pump. Precise movements and operation can be accomplished in anumber of ways, for example by driving the syringe plunger with acomputer-controlled stepper motor. Due to low cost, ease of manufacture,and established use, when appropriate, syringe devices can be furtherinnovated to provide novel functionality.

[0003] U.S. Pat. No. 2,549,417 to Brown entitled “Syringe ampoule”discusses temporary compartments for use within a hypodermic syringe.Accordingly, to provide for temporary compartments, by-pass ribs (thelength of the by-pass ribs being greater than the width of the stopper)are projected into the barrel of the syringe. In such a manner, a valveof sorts is created by projecting ribs to establish communicationbetween potentially a plurality of compartments. One use describedprovides for dry chemicals in one compartment that may be measured andtransported in the device. Subsequently, providing a fluid passage(using the ribs as a valve) allows these chemicals to be mixed with adiluent and dispensed.

[0004] U.S. Pat. No. 2,591,046 to Brown entitled “Hypodermic syringeassembly” further discusses syringe configurations and among otherthings, provides for multiple ribs so that the liquid vehicle may passthrough these passages.

[0005] U.S. Pat. No. 5,000,735 to Whelan entitled “Single use syringe”discusses general use of syringes and more particularly a means ofpreventing reuse, for example, by breaking off or otherwise separatingthe plunger or plunger gasket after downward movement.

[0006] U.S. Pat. No. 4,469,482 to Lissenburg entitled “Disposablehypodermic syringe” discusses various aspects of syringes, theircomposition and use.

[0007] U.S. Pat. No. 6,379,328 to Mac Clay entitled “Disposable syringe”discloses a novel piston design used generally for dispensing fluids,such as drugs.

[0008] U.S. Pat. No. 5,389,070 to Morell entitled “Syringe apparatuswith a fluid reservoir for injecting and aspiration of fluids” discussesadvantages of connecting more than one syringe via a three-way stopcock,for example.

[0009] Among other things, U.S. Pat. No. 6,171,285 to Johnson entitled“Retractable syringe” discusses plunger locks and needle retraction intothe syringe barrel.

[0010] Another form of plunger lock or plunger inhibitor is discussed inU.S. Pat. No. 6,368,305 to Dutton entitled “Syringe plunger immobilizingdevice”.

[0011] U.S. Pat. No. 5,480,064 to Yan entitled “Dispensing syringe for afluid glue” discusses additional aspect of operating a syringe fordispensing fluids.

[0012] U.S. Pat. No. 4,430,079 to Thill entitled “Fluid dispensingdevice” among other things discusses coupling a syringe with a hose andproviding for the application of a uniform force to the plunger to provesteady flow over a period of time.

[0013] For some applications it is useful to know the position of theplunger, as in a belt-driven infusion pump as discussed in U.S. Pat. No.5,259,732 to Stern entitled “Syringe pump with syringe barrel positiondetector”. Stern also discusses use of a pressure detector to detectocclusions. Other aspects of syringe use in infusion pumps may be foundin U.S. Pat. No. 5,295,966 to Stern. Various aspects of driving syringesis also discussed within.

[0014] U.S. Pat. No. 6,287,282 to Bonaldo entitled “Syringe safetysleeve and adaptor” discusses attachment of a protective sleeve. Otherattachments within or external to syringes, such as filters arediscussed in U.S. Pat. No. 4,137,917 to Cohen entitled “Syringe filterunit”.

[0015] U.S. Pat. No. 6,419,656 to Vetter entitled “Medical syringe withbraked step-advance plunger” discusses plunger projections as well as abypass passage forward of the piston. In certain positions theconfiguration may act with the by-pass groove and operation allows stopbumps to engage an elastically deformable brake element. At least twoaxially space projecting stop bumps are provided for on the stem orplunger rod. Vetter provides for a bypass passage forward of the plungerwhich may for example, hold a soluble medicament, but provides nomechanism to ensure that such a medicament is substantially dissolvedand dispensed. The present invention discusses internal ridges formedfrom soluble components such as medicaments and provides a means in theform of resistive changes to assess when any such components have beensubstantially dispensed. In addition, Vetter discusses pairs of stopbumps on the plunger stem that act as brake elements to prevent theplunger from advancing too rapidly requiring that the user twist thepiston to align for further advance. In some embodiments, the presentinvention seeks to simplify syringe operation providing the user withfeedback regarding syringe speed or plunger position, such tactilefeedback allowing operation of the syringe in stressful, poor lightingor other unfavorable conditions. Accordingly, Vetter does notcontemplate rings or single bumps formed on the syringe stem so as toprovide tactile feedback and does not suffer as a consequence. While thepresent invention primarily discusses ridges formed on the inner barrelof a syringe, some of this novel functionality may be derived by formingridge structures on the plunger stem.

[0016] Accordingly, because of their simplicity, ease of manufacturing,low cost, varied materials, availability, adaptability and otheraspects, it would be advantageous to further exploit the use ofsyringes. The present invention provides for a novel syringe devicewhich provides a ridge in the form of a partial or tactile stop withinthe barrel of a syringe. Such innovation provides for new functionalityand uses as will be further discussed herein.

SUMMARY

[0017] The present invention is a syringe in which one or more ridgesare formed within the barrel of the syringe or along the plunger stem ofthe syringe device to provide tactile or sensory feedback in the form ofresistive changes. The tactile feedback is useful to humans who are, forexample, visually impaired, rushed, or in low lighting situations. Thesensory feedback is also useful to machinery in automated operations.

[0018] “Ridge” as used herein means a protrusion or indentation formedwithin the barrel of a syringe or along the plunger stem of a syringedevice. A ridge as used herein may be of desired size, shape, dimension,elasticity, and number so as to provide tactile or sensory feedback,typically in the form of a resistive change to axial movement of thegasket within the barrel. Tactile feedback may be sensed by a user orvia a machine interface and provide indication of gasket position and/orspeed and/or displacement, for example. Accordingly, a ridge may besubstantially tactile, provide strong resistance to provide a stoppingor holding action, provide substantially the same or different amountsof resistance depending on the direction of axial movement, be designedfor one time use, be formed in a pattern to provide additionalindication of position or speed, or otherwise be exploited to advantage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 shows a syringe device of the present operation with noveltactile ridge.

[0020]FIG. 2a shows a syringe device of the present operation with novelimpeding ridge with plunger gasket in a forward position (prior toaspiration stroke).

[0021]FIG. 2b shows a syringe device of the present invention with novelimpeding ridge in retracted position (subsequent to an aspirationstroke).

[0022]FIG. 3 shows a syringe device of the present invention inretracted position with two impeding ridges in the syringe barrel.

[0023]FIG. 4 shows a variety of ridge configurations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024]FIG. 1 shows syringe device 100 of the present invention having acylindrical tube or barrel 110 with plunger 120 and ribbed gasket 115attached to the plunger 120. A novel, tactile ridge 125 has beenimplemented within the barrel 110. (Please note that the ridge 125 isillustrated in FIG. 1, as are all of the ridges illustrated insubsequent figures, in exaggerated size for clarity. The actual size andshape of a particular ridge depends on the use of the device.) Thetactile ridge 125 is further shown in expanded cross-section as aprotruding ring within the barrel 110. The tactile ridge 125 isimplemented so as to provide a slight, incremental resistance that maybe physically sensed as the gasket 110 is caused to move over thetactile ridge. As shown in expanded view in FIG. 1, the tactile ridge125 in this instance is formed as an internal ring. As will be describedfurther, protrusions such as bumps or indentations formed within thesyringe barrel may also be used to provide such a tactile feedback.

[0025] For many applications such tactile ridges are preferablyimplemented in a manner that does not break the seal within the syringeto a degree that undermines or otherwise impedes intended use. Thetactile ridge 125 provides feedback that may be useful to human users ormay be sensed in various ways when machine interfaced thus providinginformation regarding position or movement of the syringe plunger. Inthe illustrated embodiments, the tactile ridge 125 (225 and 331 through335 in subsequent drawings) is a rounded protrusion or nub projectingaxially from the interior wall of the barrel 210. But any shape, such assquare, rectangular, wedged, polygonal, etc., can be used, depending onthe materials used, the manufacturing process, and the degree of tactilefeedback desired.

[0026] The use of tactile feedback is advantageous in a variety ofcircumstances, for example, it may facilitate usage of a syringe for thevisually impaired. Accordingly a series or coded (patterned) series ofsuch tactile ridges could extend such functionality. Accordingly thepresent invention may be used to provide tactile feedback at volumeintervals, such as each 1 cc, may be used in conditions 160 withrestricted lighting, or may be used under conditions when it may beadvantageous to free some attention, for example, during emergencymedical situations encountered by the military or in trauma centers.Tactile ridges may be incorporated to work in conjunction with varioussyringes innovations such as compartments as previously described

[0027]FIG. 2a shows a syringe device 200 of the present invention havinga cylindrical tube or barrel 210 with ribbed gasket 215 attached toplunger rod 220. A more substantial tactile ridge in the form of animpeding ridge 225 has been implemented as a temporary impediment tomovement. As diagramed, the impeding ridge 225 provides sufficientresistance so as to keep the plunger 220 from returning past theimpeding ridge 225 when the open end 240 of the syringe is substantiallyoccluded during the aspiration stoke (plunger retraction). As theplunger 220 is retracted with the inlet occluded, a negative pressure(vacuum) is developed. Such vacuum may be exploited in a variety ofways, which will be further discussed in association with FIG. 2b.

[0028]FIG. 2b shows a syringe device 200 having a cylindrical tube 205with ribbed gasket 215 attached to the interior end plunger 220. A noveltactile ridge, in the form of an impeding ridge 225 has been implementedin the barrel of the syringe as described in association with FIG. 2a,so as to provide sufficient resistant to keep the plunger from returningto its forward position of FIG. 2a, during intended use. In thisinstance, to better describe use of the syringe 200 as a vacuum device,the syringe tip 240 is shown attached to a filter apparatus 245. Thefilter apparatus 245 is submerged in a vessel containing a particlesuspension 250. When submerged, the plunger is retracted from itsforward position of FIG. 2a, which is accomplished by retracting thesyringe plunger, thereby forcibly drawing the gasket 215 over to the topside of the impeding ridge 225. Such movement initiates the aspirationof particle suspension and will continue, typically until the vacuum isdepleted or other factors effect the system. Material captured by thefilter apparatus could be examined microscopically, for example. Otheradvantages of such a configuration are discussed in co-pending UnitedStates patent application entitled Method of Depositing Material andDensity Gradients of Material from Sample Suspensions and Filter Devicesfor Same, filed on Aug. 26, 2002.

[0029] As an example of another configuration ridge for tactilefeedback, an indentation 235 is shown in the barrel 210 in FIGS. 2a and2 b. This indentation 235 is preferably of less width than the width ofthe gasket 215, or the gasket 215 is selected of material of sufficientelasticity, in order to prevent leakage around the gasket 215. As theplunger 220 moves the gasket 215 axially within the barrel 210, the userwill feel different sensations as the gasket 215 moves over a protrudingridge 225 than when the gasket 215 moves over an indentation 235. Theindentation 235 therefore provides the user with more detailed feedbackas to the location of the plunger 220 within the barrel 210. Asdiscussed above with respect to different shapes of the protruding ridge225, this difference is sensation may be exploited for differentapplications.

[0030]FIG. 3 shows another configuration and use of syringe device 300of the present invention. As diagramed the syringe device has fiveridges identified as 331, 332, 333, 334, and 335. The uppermost ridge331 has been designed as a wedge to facilitate assembly of the syringedevice (insertion of the plunger gasket assembly into the barrel 310)and inhibit separation of these components. For some applications, or toprevent spillage, for example, it may be desirable to provide such animpeding ridge 331 in the vicinity of the upper barrel of the syringe300. Typically such impediment should be implemented so as not toinadvertently dislodge the gasket if disassembly is required or desired.

[0031] Beginning with the plunger 320 down (not shown) and the tipportion of the syringe 300 submerged in fluid 350 as shown, fluid 350may be aspirated into the syringe 300 by retracting the plunger 320,drawing attached gasket 315 to ridge 332, a position in this instanceintended to aspirate slightly more fluid 350 than is required for use,in the form of a priming volume to purge trapped air, for example.Typically, the syringe 300 is then inverted to facilitate priming whichis accomplished by advancing the plunger 320 from ridge 332, to, in thisinstance, tactile ridge 333. Then the plunger 320 may be furtheradvanced from tactile ridge 333 to another, in this instance tactileridge 334. As illustrated, the ridges are formed on the interior wall ofthe barrel 310 as a series of round shaped protrusions or nubs, but canbe of a different shape or size, or even of varying shapes and sizes, inorder to provide more detailed tactile feedback. As described, thismovement displaces the fluid volume 361 that exists between the tworidge positions 333 and 334. To provide additional indication ofposition or volume, accompanying markings striations 341 and 342 havebeen formed externally on barrel 310. In such a manner, the syringedevice 300 provides a means to dispense preset fluid volumes with ease,and relative accuracy while providing indication of the position of thegasket 315 during operation.

[0032] Advancement of the plunger 320 may continue from ridge 334 (forexample after waiting ten seconds) as required or desired, to tactileridge 335, therefore in this instance providing a level of control overthe dispensing of two fluid volumes, over a desired time interval.

[0033] The dimensions and sizes of the ridges 331 through 335 and thematerials of the syringe barrel 310 should be considered for use. Forexample, gaskets with relatively elastic properties (e.g. rubber likecompounds) will understandably perform different than firmer Tefloncoated plastics or other materials. A small striation, scribe or bumpencountered by a Teflon gasket may provide sufficient tactile feedbackwhereas a more substantial ridge may be required to achieve the sameends, employing a more elastic material. As describe, ridges of varioustypes may be formed or distributed over an effective area to providesufficient tactile resistance. Rounded contact surfaces, to minimizeabrasion to the gasket 315 are preferable but not required by the scopeand intent of the present invention. Similarly, extended ridges in theform of narrowings or widenings of the syringe body are also consideredwithin the scope of intended functionality of the present invention.

[0034]FIG. 4a shows an alternative embodiment. In this embodiment, theridge is formed by a tapering of the barrel of the syringe, along someportion or even substantially all of the syringe barrel. When thesealing gasket 401, with appropriate elastic properties, is insertedinto the hollow cylindrical syringe barrel 402 and moved fromapproximate position 403, in the direction of the arrow 405, towardsapproximate position 404, an increase in resistance is generated due tofrictional forces. This increase may be sensed, by a human user ormachine-sensors interfaced to the plunger (not shown) and exploited toprovide information as to the position of the sealing gasket 401 withinthe barrel 402. The syringe device is so formed and materials selectedso that the seal between the sealing gasket 401 and the barrel 402 issubstantially maintained during operation. If required or desired,however, the resistance, for example in approximate area 404, could besubstantial enough to act as a mechanical stop, for intended use.

[0035]FIG. 4b shows a embodiment in which different resistances aregenerated in different sections of the barrel of the syringe. In thisembodiment, sealing gasket 411 is advanced, typically by pushing or pullit via the attached plunger (not shown), through approximate regions412, 413, and 414. During passage through region 412, the sealing gasket411 encounters constant resistance. During passage through region 413,an increase in resistance is generated, and sensed. The resistance thenremain relatively constant over some other a region of the syringebarrel, such as that designated as 414. Various forms of tapering may beimplemented as required or desired to provide feedback to the human useror machine-interfaced sensors.

[0036]FIG. 4c shows other embodiments of ridges in the form ofdeformable tabs projecting into the interior wall of the syringe barrel422. Ridges 423 are designed and intended in this instance to provide acertain resistance to movement as the sealing gasket 421 is pushed overthem in the direction of movement indicated by arrow 425. Similarly,when the sealing gasket 421 is moved over these ridges 423 in theopposite direction, the design and implementation provides slightly lessresistance than was generated in direction 425. Further along syringebarrel 422, ridges 413 have been implemented as distributed tabs aroundthe interior of the barrel 422, providing a resistance increase that islower in direction 425 and higher in the opposite direction.Alternatively, these ridges may take the form of a ring 424, projectingcircumferentially around the interior of the barrel 422, instead of astabs.

[0037]FIG. 4d shows sealing gasket 431 for insertion into syringe barrel432 having ridges 433 formed on the interior wall of barrel 432 in theform of coded bumps. The number and interval of resistive pulsesgenerated and sensed as the sealing gasket 431 is advanced over them,provides information such as position, movement, speed, or displacedvolume. Such information may be useful as sensed by the visuallyimpaired, in poor lighting conditions, etc. Also, machine-interfacedsensors could employ this information to advantage, for example, tosimplify position detection or otherwise provide feedback for roboticoperation. Alternatively, for the same stroke distance, using largersyringe barrels may simplify the mechanics or electronics necessary toaccomplish a desired task. Similarly, in certain situations, such asisolating electronics from fluids may favor such implementation. Analternate series of ridges in the form of nubs 434 are designed toprovide information in the form of resistive pulses that change inmagnitude as gasket 431 is caused to pass over them. Both ridges 433 andnumbs 434 can project as tabs from the interior of the barrel 432 or ascircumferential rings projecting from the interior of the barrel 432, asdescribed above with respect to FIG. 4c. The number, size, position,sequence, and resistance of the ridges 433 or numbs 433 can be designedas needed to provide feedback to the human user or themachine-interfaced sensor.

[0038]FIG. 4e shows additional embodiments with ridges of various typesformed as indentations in the interior wall of the syringe barrel 442 soas to provide resistive changes as the sealing gasket 441 passes overthem, is delayed by them, or its motion is substantially halted, asdesired or required. The sealing gasket 441 has been designed and inthis instance customized to operate in this barrel 442. Additionally,ridge 448 has been formed as a protruding ridge in the form of acollapsible bubble, designed to be sensed once, thereafter providing nofurther resistive change, if subsequently encountered. Alternatively,such a single sense element could be reversed in curvature and sprunginto an adjacent indentation, or alternatively a single sense elementcould be a break-off or otherwise separating component, as required ordesired.

[0039] Another useful form of ridge could be provided by chemicalsformed, for example, as rings within the barrel 442. In this instancethe ridge resistance may provide information regarding mixing, quantityof dissolved chemical dispensed, etc.

[0040] While preferred embodiments of the present invention are shownand described, it is envisioned that those skilled in the art may devisevarious modifications of the present invention without departing fromthe spirit and scope of the appended claims.

I claim:
 1. A syringe device comprising a hollow cylindrical memberhaving an inner wall, a sealing gasket disposed within said cylindricalmember, a plunger connected to said sealing gasket, said plungerimplemented to drive said sealing gasket substantially axially withinsaid cylindrical member, at least one ridge formed on said inner wall,said at least one ridge providing a change in resistance to saidsubstantially axial movement of said sealing gasket within saidcylindrical member.
 2. The device of claim 1, wherein said at least oneridge comprises at least one tab.
 3. The device of claim 1, wherein saidat least one ridge comprises a continuous ring.
 4. The device of claim1, wherein said at least one ridge comprises a collapsible bubble. 5.The device of claim 1 wherein the movement of said gasket over said atleast one ridge causes an increase in said resistance.
 6. The device ofclaim 1 wherein the movement of said gasket over said at least one ridgeprovides a resistive change in the form of a decrease in resistance. 7.The device of claim 1 wherein said at least one ridge is made of amaterial that dissolves when a solvent is aspirated.
 8. The device ofclaim 7, wherein said change in resistance provides a continuedindication of a continued presence of a material, not yet dissolved insaid solvent.
 9. The device of claim 1 wherein said at least one ridgecomprises a plurality of ridges.
 10. The device of claim 9, wherein saidplurality of ridges are arranged in a sequence.
 11. The device of claim9, wherein said plurality of ridges have at least two different sizes orshapes, wherein said change in resistance depends on the size of saidsize or shape.
 12. A syringe device comprising a hollow cylindricalmember having an inner wall, said inner wall having an inner diameter, asealing gasket disposed within said cylindrical member, a plungerconnected to said sealing gasket, said plunger implemented to drive saidsealing gasket substantially axially within said cylindrical member, aridge formed on said inner wall, wherein said ridge comprises a taperingof said inner diameter, said tapering providing a change in resistanceto said substantially axial movement of said sealing gasket within saidcylindrical member.
 13. The device of claim 12, wherein said taperingcomprises a predetermined pattern.
 14. A syringe device comprising ahollow cylindrical member having an inner wall, a sealing gasketdisposed within said cylindrical member, a plunger connected to saidsealing gasket, said plunger implemented to drive said sealing gasketsubstantially axially within said cylindrical member in a firstdirection and in a second direction, at least one ridge formed on saidinner wall, said at least one ridge providing a first change inresistance to said substantially axial movement of said sealing gasketwithin said cylindrical member in said first direction and a secondchange in resistance in said substantially axial movement of saidsealing gasket within said cylindrical member in said second direction.15. The device of claim 14, wherein said at least one ridge comprises atleast one tab.
 16. The device of claim 14, wherein said at least oneridge comprises a continuous ring.
 17. The device of claim 14, whereinsaid at least one ridge comprises a collapsible bubble.
 18. The deviceof claim 14, wherein the movement of said gasket over said at least oneridge causes an increase in said resistance.
 19. The device of claim 14,wherein the movement of said gasket over said at least one ridgeprovides a resistive change in the form of a decrease in resistance. 20.The device of claim 14, wherein said at least one ridge is made of amaterial that dissolves when said gasket moves over said ridge.
 21. Thedevice of claim 14, wherein said at least one ridge comprises aplurality of ridges.
 22. The device of claim 21, wherein said pluralityof ridges are arranged in a sequence.
 23. The device of claim 21,wherein said plurality of ridges have at least two different sizes,wherein said change in resistance depends on the size of said size. 24.A method of sensing the volume of fluid moved by a syringe, comprisingdriving a gasket substantially axially within a hollow cylindricalmember having an inner wall to aspirate and dispense said fluid, andsensing a change in resistance caused by the movement of said gasketover at least one ridge formed on said inner wall.
 25. The method ofclaim 24, wherein said at least one ridge comprises at least one tab.26. The method of claim 24, wherein said at least one ridge comprises acontinuous ring.
 27. The method of claim 24, wherein said at least oneridge comprises a collapsible bubble.
 28. The method of claim 24,wherein the movement of said gasket over said at least one ridge causesan increase in said resistance.
 29. The method of claim 24, wherein themovement of said gasket over said at least one ridge provides aresistive change in the form of a decrease in resistance.
 30. The methodof claim 24 wherein said at least one ridge is made of a material thatdissolves when said gasket moves over said at least one ridge.
 31. Themethod of claim 24 wherein said at least one ridge comprises a pluralityof ridges.
 32. The method of claim 31, wherein said plurality of ridgesare arranged in a sequence.
 33. The method of claim 31, wherein saidplurality of ridges have at least two different sizes, wherein saidchange in resistance depends on the size of said size.
 34. A method ofsensing the volume of fluid moved by a syringe, comprising driving agasket substantially axially within a hollow cylindrical member havingan inner wall to aspirate and dispense said fluid, and sensing a changein resistance caused by the tapering of the inner diameter of saidcylindrical member.
 35. The method of claim 34, wherein said taperingcomprises a predetermined pattern.
 36. A method of sensing the volume offluid moved by a syringe, comprising an aspiration step comprisingdriving a gasket substantially axially within a hollow cylindricalmember having an inner wall to aspirate said fluid, a dispensing stepcomprising driving a gasket substantially axially within saidcylindrical member to dispense said fluid, sensing a first change inresistance caused by the movement during said aspiration step of saidgasket over at least one ridge formed on said inner wall, sensing asecond change in resistance caused by the movement during saiddispensing step of said gasket over said at least one ridge.
 37. Themethod of claim 36, wherein said at least one ridge comprises at leastone tab.
 38. The method of claim 36, wherein said at least one ridgecomprises a continuous ring.
 39. The method of claim 36, wherein said atleast one ridge comprises a collapsible bubble.
 40. The method of claim36, wherein the movement during said aspiration step of said gasket oversaid at least one ridge an increase in said resistance.
 41. The methodof claim 36, wherein the movement during said dispensing step of saidgasket over said at least one ridge causes an increase in saidresistance.
 42. The method of claim 36, wherein the movement during saidaspiration step of said gasket over said at least one ridge causes adecrease in said resistance.
 43. The method of claim 36, wherein themovement during said dispensing step of said gasket over said at leastone ridge causes a decrease in said resistance.
 44. The method of claim36, wherein said at least one ridge is made of a material that dissolveswhen a solvent is aspirated.
 45. The method of claim 36, wherein said atleast one ridge comprises a plurality of ridges.
 46. The method of claim45, wherein said plurality of ridges are arranged in a sequence.
 47. Themethod of claim 45, wherein said plurality of ridges have at least twodifferent sizes, wherein said change in resistance depends on the sizeof said ridges.
 48. A syringe device comprising a hollow cylindricalmember having an inner wall, a first end, and a second end, a sealinggasket disposed within said cylindrical member, a plunger connected tosaid sealing gasket, said plunger implemented to drive said sealinggasket substantially axially within said cylindrical member, a structureat said cylindrical member first end forming a cutout, said plungermoving axially through said cutout to drive said sealing gasket in afirst direction toward said first end and in a second direction towardsaid second end, at least one ridge formed on said plunger, said atleast one ridge providing a change in resistance to said substantiallyaxial movement of said plunger through said cutout.
 49. The device ofclaim 48, wherein said at least one ridge comprises at least one tab.50. The device of claim 48, wherein said at least one ridge comprises acontinuous ring.
 51. The device of claim 48, wherein said at least oneridge comprises a plurality of ridges.
 52. The device of claim 51,wherein said plurality of ridges are arranged in a sequence.
 53. Thedevice of claim 51, wherein said plurality of ridges have at least twodifferent sizes or shapes, wherein said change in resistance depends onthe said size or shape.
 54. A syringe device comprising a hollowcylindrical member having an inner wall, a first end, and a second end,a sealing gasket disposed within said cylindrical member, a plungerconnected to said sealing gasket, said plunger implemented to drive saidsealing gasket substantially axially within said cylindrical member in afirst direction and in a second direction, a structure at saidcylindrical member first end forming a cutout, said plunger movingaxially through said cutout to drive said sealing gasket, at least oneridge formed on said plunger, said at least one ridge providing a firstchange in resistance to said substantially axial movement of saidplunger through said cutout in said first direction and a second changein resistance in said substantially axial movement of said plungerthrough said cutout in said second direction.
 55. The device of claim54, wherein said at least one ridge comprises at least one tab.
 56. Thedevice of claim 54, wherein said at least one ridge comprises acontinuous ring.
 57. The device of claim 54, wherein said at least oneridge comprises a plurality of ridges.
 58. The device of claim 57,wherein said plurality of ridges are arranged in a sequence.
 59. Thedevice of claim 57, wherein said plurality of ridges have at least twodifferent sizes or shapes, wherein said change in resistance depends onthe said size or said shape.
 60. A method of sensing the volume of fluidmoved by a syringe, comprising driving a plunger connected to a gasketsubstantially axially within a hollow cylindrical member to aspirate anddispense said fluid, said cylindrical member having a first end, asecond end, and a structure at said cylindrical member first end forminga cutout, and sensing a change in resistance caused by at least oneridge on said plunger as said at least one ridge encounters said cutout.61. The method of claim 60, wherein said at least one ridge comprises atleast one tab.
 62. The method of claim 60, wherein said at least oneridge comprises a continuous ring.
 63. The method of claim 60, whereinsaid at least one ridge comprises a plurality of ridges.
 64. The methodof claim 63, wherein said plurality of ridges are arranged in asequence.
 65. The method of claim 63, wherein said plurality of ridgeshave at least two different sizes or shapes, wherein said change inresistance depends on the said size or said shape.
 66. A method ofsensing the volume of fluid moved by a syringe, comprising an aspirationstep comprising driving a plunger connected to a gasket substantiallyaxially within a hollow cylindrical member to aspirate said fluid, adispensing step comprising driving said plunger connected to said gasketsubstantially axially within said cylindrical member to dispense saidfluid, said cylindrical member having a first end, a second end, and astructure at said cylindrical member first end forming a cutout, andsensing a first change in resistance caused by at least one ridge onsaid plunger as said at least one ridge encounters said cutout duringsaid aspiration step, sensing a second change in resistance caused bysaid at least one ridge as said at least one ridge encounters saidcutout during said dispensing step.
 67. The method of claim 66, whereinsaid at least one ridge comprises at least one tab.
 68. The method ofclaim 66, wherein said at least one ridge comprises a continuous ring.69. The method of claim 66, wherein said at least one ridge comprises aplurality of ridges.
 70. The method of claim 69, wherein said pluralityof ridges are arranged in a sequence.
 71. The method of claim 69,wherein said plurality of ridges have at least two different sizes orshapes, wherein said change in resistance depends on the said size orsaid shape.